KexExchange is generally broken and needs replacement

[eugeneia]

It would be generous to call the current key exchange protocol a proof of concept. (: It needs to be replaced with something sensible.

References:

• IKEv2
• ECDH
• libsodium constructions
• Noise protocol

[eugeneia]

A friendly person has suggested taking inspiration from the spiped protocol. I am wondering if we can "instantiate" the spiped protocol using algorithms recommended by libsodium (which Vita does already link), i.e. HMAC-SHA512256, ARGON2 and BLAKE2B-512(X25519(p.n)) with equal or better security properties.

I am favoring the spiped protocol’s key exchange so far because it matches Vita’s model very well, and is more concrete(?) than Noise.

[eugeneia]

One thing to note is that both Noise and spiped are rather TCP/stream oriented, while Vita’s key exchange is packet oriented. Have to take an extra close look at the implications thereof.